Planetary postcards

Did you know that there are only four terrestrial planets in the Solar system with a significant atmosphere, and we’ve taken photographs from the surface of all four of them?

Earth, Venus, Mars, and Titan. It shouldn’t be too hard to figure out which is which, but clicking on them will give you a bigger picture, and your answer.

Incidentally, I didn’t really like the Venus image as I found it, so I updated it to try and better reflect the few Soviet Venera images which were in colour.

Incidentally, as a terrestrial object with a significant atmosphere, the case could probably be argued for Triton too. And yes, I’m classing moons as planets here. I don’t like to discriminate against planets based on their orbital characteristics. I’m an equal opportunities astronomer.

Earth image courtesy of A Pacific View!

About Invader Xan

Molecular astrophysicist, usually found writing frenziedly, staring at the sky, or drinking mojitos.
This entry was posted in astronomy and tagged . Bookmark the permalink.

4 Responses to Planetary postcards

  1. Baribal says:

    Are all pictures in the human-eye spectrum? I’d have expected Venus to be under a black layer of clouds, somehat Matrix-like.

    • invaderxan says:

      They’re all taken in optical light, as far as I know – though I’m afraid I have no idea about the exposures. The Venus image in particular is remastered from the Soviet Venera probes. I believe it’s been adjusted to compensate for bad lighting, and I know for a fact that it’s in false colour.

      In short, both Titan and Venus would probably appear a bit darker to human eyes than they appear in these images. :)

    • Prof. Bleen says:

      This paper says that the surface illumination of Venus is about 5000-10,000 lux, which is brighter than an overcast day on Earth. That’s quite a surprise to me, as I was thinking of Larry Niven’s “searing black calm.”

      • invaderxan says:

        Fascinating… I hadn’t seen that paper before, thanks!

        I suppose it makes sense when you think about it. After all, Venus receives nearly twice as much sunlight as Earth, and all of that atmosphere would diffuse the light reaching the surface to give backscattered light as well as direct… Though that last point is speculation on my part.

Comments are closed.